1. Field of the Invention
The present invention relates generally to a method and an apparatus for distributing particles. More specifically, the invention relates to a method and an apparatus for directing the movement of particles such as blocks to efficiently form electronic assemblies.
2. Background
The manufacture of electronic assemblies such as display panels is known in the art. One such method involves using fluidic self-assembly (FSA) that is described in U.S. Pat. No. 5,545,291. In FSA, blocks with integrated circuits thereon are placed into a fluid such as water. The combination of blocks in a fluid, referred to as a slurry, is dispensed over recessed regions in a substrate. The recessed regions receive the plurality of blocks and the blocks are subsequently electrically coupled. Although FSA has provided advantages to electronic device manufacturers such as increased speed of assembling an electronic device, for economic reasons it is necessary to dispense an excess amount of blocks, and recover those blocks that fall to the surface of the substrate without settling into recessed regions. Additionally, because FSA is a stochastic process, initially, some of the recessed regions may not be filled by a block. This is problematic because devices manufactured with some recessed regions that lack a block generally operate less efficiently compared to devices in which all of the blocks have been properly placed. A manufacturer may solve this problem by using a variety of methods. For example, the FSA process may be used a second time over the empty recessed regions. Another method involves using a robot to place a block into a particular recessed region. Typically the robot may not place more than one block into one of the recessed regions. Using the robot is a time consuming and expensive process.
There are other challenges inherent in the FSA process. For example, the slurry must be transported from one process chamber to the next. However, typical fluid control components, such as valves, cannot be used because these components could potentially crush a block, thereby polluting the process chamber with particulate matters. The movement of blocks also cannot be controlled near the recessed regions of the substrate to either direct a block to move into a particular recessed region or to move excess blocks away from recessed regions that are already filled. It is therefore desirable to have a method and an apparatus that address these problems associated with conventional systems.